Geo2:Chapter 9

The flashcards below were created by user
dante01
on FreezingBlue Flashcards.

Evolution

-genetically controlled changes in physiology, anatomy and behavior that occur over time

Clade

different species with the same ancestor

Speciation

the development of two or more different species from a single common ancestor species

Gregor Mendel and origin of genetics

-father of genetics

-Pea experiments

-Units of inheritance do not change or blend

Basic principle of genetics

1. Genes

-chemical unit of heredity

-formed of DNA

2. DNA

-a molecule with a double helix structure

Polymorphism

genetically controlled variation in appearance within a population

Genome

full range of genes present in a species

Phenotypic variations

differences in physiology,anatomy, or behavior within a species

Genotypic variations

genetic differences within a species

Mutations

random changes in the genes or chromosomes of a cell

Cline

a geographic gradient in a genetically controlled trait

Hybridization

sexual reproduction between two different species

Natural Selection

the process by which the genes for genetically controlled traits become more common in a population over time because individuals with those traits are reproductively more successful than other individuals

Speciation

The development of two or more different species from a single common ancestor species

Reproductive isolation

there should be a barrier between a new species and an original species

Environmental controls: ranges of tolerance and ecological optimum

1. Ranges of tolerance

-determine where on Earth a species may be found

2. Ecological optimum

-the environmental conditions under which a species will prosper

Stasis

long period of time with no evolutionary changes

Phyletic gradualism

a slow steady process

Punctuated equilibrium

speciation occurs within an originally small group, which later expands

Direction in evolution

There are patterns but no general direction

Geography and evolution: Founder principle, bottleneck

1. Founder principle

-small isolated populations have less genetic variation than the main population.

-favors allopatric speciation

2. Bottleneck

-decrease in genetic diversity as a result of a significant decrease in population size

Vicariance

geological event of environmental changes that splits a range of species in tow isolated partys

Adaptive radiation

formation of several species from a single ancestor

Convergent and divergent evolution and examples of

1. Convergent evolution

-the development of similar traits in unrelated species living in similar environments

Ex. Tenrec and Hedgehog

2. Divergent evolution

-separation of a species into new types

Ex. Aardvark, numbat and anteater

Parallel evolution and coevolution

1. Parallel evolution

-geographically isolated populations derived from the same ancestor evolve into morphologically and physiologically similar descendant species

2. Coevolution

-two unrelated species evolve traits that are tied to their interaction

Extinction

total loss of a species, genus, family, or order

Types of extinction

1. Local extinction

-a species disappears in one area but persists in others

2. Global extinction

-a species disappears completely

3. Phyletic extinction

-when a species/genus evolves into a new species/genus

Trophic cascade

the loss an important prey species causes further extinctions for higher predators

Ex. California condor

Living fossils

persist without considerable evolutionary changes for a geologically long time